Lecture - 2 (Pairs or joints)

JOINTS 
Any connection between two links is always known as joint or a pair.

Different types of joints

  • BINARY JOINTS - when two links are connected it forms a binary joints. Examples are listed below:
    Sliding pair and turning pair

    Turning pair

  • TERNARY JOINTS - when 3 links are connected it forms a ternary joints. One ternary joint is equivalent to two binary joints.
    Turning pair forms by joining 3 links
  • QUATERNARY JOINTS - when 4 links are connected it forms a quaternary joint. One quaternary joint is equivalent to three binary joints.
Here in quaternary joints - (1-2) link, (1-3) link, (1-4) link, (2-3) link, (3-4) link & (2-4) link all 6 are binary joints but notice that if you intoduce any 3 binary joints the rest 3 binary joints will automatically come and thus a quaternary joint formed. So we can conclude that 3 binary joints are dependent on other 3 binary joints. Therefore 1 quaternary joint is equivalent to 3 binary joints as we have 3 independent binary joints

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